This invention relates to an anchoring device, and more particularly, to a concrete anchor which is embedded in a concrete ceiling for suspension of a ceiling panel, electrical wiring pipe, air conditioning device, or the like.
Concrete anchors are well known in the prior art. They provide a means to hang building systems from concrete ceilings. The anchors are installed prior to pouring the concrete into a form that creates the level of a building. The concrete anchors are located in the ceiling at the proper locations by attaching them to the form that supports the concrete as it is hardening. The best concrete anchors are inexpensive to make and assemble, are quickly placed in the proper position on the form, are resistant to cement entering into the working mechanisms of the anchor, and can accept a variety of sizes of threaded rods for supporting the building elements. U.S. Pat. No. 1,940,545, issued in 1933 to Holmes, teaches an early concrete anchor made from cast iron and is hereby incorporated by reference. U.S. Pat. No. 3,405,497, issued in 1968 to McNair, teaches a modern concrete anchor made from both metal and plastic components to reduce the cost of manufacture and is hereby incorporated by reference. The use of plastic components also facilitates identification of the anchors by using differing colors of plastic which can be used to instruct users about the size of rod that can be used with the anchor. U.S. Pat. No. 4,211,048, issued in 1980 to Naka, also teaches a concrete anchor made from both metal and plastic components and is hereby incorporated by reference. The Naka patent focused on improving the manner in which the anchor is connected to the form. Naka shaped the parts, particularly the top of the anchor, so that the nails that attach the anchor to the form can be driven simultaneously. Published Japanese Patent Application 5-230893, filed in 1982, teaches a concrete anchor where the anchor receiving portion is made with a plurality of internal diameters so that one anchor can receive different sized threaded rods. U.S. Pat. No. 6,240,697, issued in 2001 to Thompson et al, also teaches a concrete anchor made from both metal and plastic components that can receive threaded rods of multiple diameters, the contents of which are hereby incorporated by reference.
A problem with all of the concrete anchors taught by the prior art is that the rod needs to be threaded into the anchor. This slows down installation of the suspended system and can be difficult as the user is generally working from below. There are a number of systems in the prior art where a threaded member is received by a slip nut or other device to hold the threaded member in place without having to thread the rod into the slip nut. U.S. patent application Ser. No. 13/531,159, filed Jun. 22, 2012, teaches an automatic take-up device that has threaded inserts that can receive a threaded rod without having to rotate the threaded rod into the device, the contents of which are hereby incorporated by reference.
The present invention provides a concrete anchor with inserts that can receive a threaded rod without having to thread the rod into the device that can be used with confidence in a concrete anchor where the anchor will be encapsulated by concrete and otherwise inaccessible to the user except for inserting the rod into place.